Immersed Boundary Method

Lattice Boltzmann Method LBM: Theory
#1

Hello,

does anybody know where to find a working Immersed Boundary Method code?
Is the openLB code capable of dealing with it?

Thanks,
Timm

#2

Hello,
what do you mean by “Immersed Boundary Method”?

#3

The IBM is a method to take into account particles in a fluid. The particles (rigid or elastic) are described by a surface mesh. One can then calculate the interaction of the fluid and the mesh by interpolation between the two coordinate systems. The fluid system is called Eulerian, the particle system Lagrangian. Of course this approach is non-local but “nearly local” since usually only information of the next neighbors is required. There is a review by Mittal and Iaccarino: “Immersed Boundary Method”, Annu. Rev. Fluid. Mech. (2005) 37:239-61.
This method is predestinated for the simulation of elastic particles (e. g. cells) in fluids and thus very interesting for me.

#4

Hi,
I don’t know such code. But I would say that it could be done with openLB by using the coupling of different kind of objects (as it is done in the multispecies shan-chen model, or the thermal coupling).

#5

Thanks, I will study the openLB code (in the next weeks) and see if I can apply it to my problem.

Timm

#6

Hello Timm,

I am totally new to LBM and openLB and I would like to model a unique deformable particle sumbitted to shear forces in a flow within highly complex geometries.
I am really attracted by the IBM method you successfully implemented in your article “Efficient and accurate simulations of deformable particles immersed in a fluid using a combined immersed boundary lattice Boltzmann finite element method”.

I am wondering : did you managed to implement it in the openLB code or did you start over with your own code? How long did it take (I need to get quick results for my thesis)?

Thanks,

Michael

#7

Hi Michael,

I used my own LB code, but I see no problem to implement a deformable particle on top of OpenLB. Writing the code for IBM is quite easy, it can be done within one week. A larger problem is the correct coding of the membrane forces. What kind of ingredients do you want? Strain forces, area dilation forces, bending forces, viscous forces? What does “highly complex” mean?

Best,
Timm

#8

Hi Timm,

Sounds encouraging. I think that in my particular case, I’ll have enough getting the strain forces and assuming that I have volume and surface conservation. I believe that bending forces are much more difficult to compute. Am I right?

By “highly complex”, I meant a bio-related cavity with possibly moving walls. That’s why the stl reading feature of OpenLB is so attractive… If you are interested in more details, I can send you an email.

Thanks for the quick answer!
Best,

Michael

#9

Yes, it would be nice if you could send me a mail (you find the address in my profile here).
Timm